The 30-share barometer, which gained over 511 points in the previous session, fell by 70.89 points, or 0.36 percent to 19,531.34 in the first few minutes of trade on Monday, led by a fall in oil and gas, metal and power sector stocks.

According to market experts, the trading sentiment turned somewhat weak after Reliance Industries reported a 14 percent rise in net profit for the quarter ended March 31, 2011, well below the market's expectations.

The most-weighted firm on the Sensex, Reliance Industries fell sharply by 2.40 percent to Rs 1,015 in opening trade.

Meanwhile, the Hong Kong Hang Seng index gained 1.01 percent and Japan's Nikkei was trading 0.29 percent up in early trade on Monday.